Which EKG finding is commonly associated with digitalis toxicity?

The finding commonly associated with digitalis toxicity is a downsloping ST segment, often referred to as a "scooped" ST segment. This characteristic change occurs due to the drug's effect on myocardial cells, influencing the electrical activity of the heart. Digitalis increases intracellular calcium concentration, which enhances myocardial contractility but can also lead to changes in the heart's repolarization process. The resulting downsloping, or "scooped" appearance of the ST segment is a hallmark of how digitalis alters the normal electrocardiographic patterns, particularly in the setting of toxicity.

Other options present changes that are not specifically linked to digitalis toxicity. For instance, widening of the QRS complex can be associated with various other conditions, such as bundle branch blocks or hyperkalemia, but it is not a primary indicator of digitalis effects. Flat T waves are often related to electrolyte imbalances or ischemic conditions but do not specifically indicate digitalis toxicity. Shortened QT intervals can occur in response to high calcium levels but are not a typical finding with digitalis. Understanding these associations helps frame the significance of the downsloping ST segment as a specific indicator of digitalis toxicity.